Marc co-founded Riot – along with Brandon Beck – in 2006 with the vision and commitment to drastically change the way video games are developed, delivered, and supported for players. Since then, he’s helped League of Legends become the most-played online game in the world and a key driver of the growth of esports. Riot continues to uphold their "player first" vision by devoting the entire company's activity around prioritizing the player experience, and has been acclaimed for its focus on balanced game design, community engagement, and pioneering work in establishing games as a service. Riot Games is headquartered in Los Angeles, CA and has ~3,000 employees across 23 offices around the world to support players globally.

Marc is also active outside of Riot and serves on the board of several non-profit organizations, including: Unite America, focused on addressing the polarized gridlock in Washington; City Year Los Angeles, focused on lowering the dropout rate in the worst performing schools in the nation's toughest neighborhoods; and the Seal Family Foundation. Marc has also been recognized with several awards such as the Ernst & Young Entrepreneur of the Year award, several Game Developers Choice Awards and a BAFTA.